6.9.3 Solving Static Equilibrium Problems Flashcards
Solving Static Equilibrium Problems
• The conditions for equilibrium:
A thin weightless rod with a length of 4m is subjected to forces F1, F2, F3, and F4. Each of the forces has a magnitude of 5N. What is the magnitude of the torque?
20 sin 60° mN
A weightless bar with a length of 3 m is supported by two vertical ropes. There are four weights hung from the bar: W1 = 10N, W2 = 6N, W3 = 20N, and W4 = 40N. Which of the following are the tensions F1 and F2 in the ropes?
F1 = 25.7N F2 = 40.3N
If an object is in translational equilibrium, ___________________.
the sum of the forces in the upward direction equals the sum of the forces in the downward direction
A thin weightless rod with a length of 4m is subjected to forces F1, F2, F3, and F4. Each of the forces has a magnitude of 10N. There the pivot is at position P. The rod is in __________
translational, but not rotational, equilibrium
A lever of length h is used to lift a weight W positioned at one end of the lever. The lever has mass m. The fulcrum is at a distance y from the weight. What is the magnitude of the force needed at the end of the lever to have static equilibrium?
F = 2Wy + (2y-h)mg / 2(h-y)
A weight W is hung from a weightless bar a distance d1 from the pivot point. The bar is supported at its right end by a pivot and at its left end by a cable that exerts a force T. The length of the bar is d2. The angle that the cable makes with the bar is theta. Which of the following is the relationship between T and W?
T = Wd1/(d2sin theta)
A ladder with a mass of 15kg rests against a smooth wall. A person with a mass of 78 kg stands on the ladder. The perpendicular distance from the point the ladder touches the ground to the extensions of W1 equals 1.0m, and to the extension of Wm equals 1.6m. The weight vector of the ladder is W1, and Wm is the weight vector of the person. The top of the ladder is 5.6m from the ground. What frictional force must act on the bottom of the ladder to keep it from slipping?
2.4*10^2 N
Three weights are positioned on a weightless rod. Weight 1 (W1) equals 2N and is at x1 = 1m. Weight 2 (W2), which equals 5N, is at x2 = 2m. Weight 3 (W3), which equals 10N is at x3 = 4m. Where is the center of gravity of this system?
3 1/17
